/*=====================================================================*
 *                   Copyright (C) 2011 Paul Mineiro                   *
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#ifndef __POWER_LAW_LEARNING_RATE_HH__
#define __POWER_LAW_LEARNING_RATE_HH__

#include "learningrate.hh"

#include <cmath>

namespace flassol
{
  class PowerLawLearningRate : public LearningRate
    {
      private:
        static LearningRateFactory factory;

        double initial_t;
        double power_t;
        double initial_rate;

      public:
        explicit
        PowerLawLearningRate (double _initial_rate = 1.0,
                              double _initial_t = 1.0,
                              double _power_t = 0.0)
          : initial_t (_initial_t),
            power_t (_power_t),
            initial_rate (_initial_rate * pow (initial_t, power_t))
          {
          }

        virtual float
        eta (double t) 
          {
            return initial_rate / pow (t + initial_t, power_t);
          }
    };
}

#endif // __POWER_LAW_LEARNING_RATE_HH__
